The invention relates to a device for mutually connecting by welding of sheet-metal objects, for instance flat plates. The use of laser welding for this purpose is known. The use of a laser is necessary herefor. Suitable lasers capable of generating infrared radiation of the desired wavelength range are for instance YAG lasers or CO.sub.2 lasers. By means of optical means, for instance lenses, mirrors or the like, a very intense beam of infrared radiation is directed at the weld location. The beam is of the convergent type and the weld location will generally be situated roughly in the focal spot of the optical system.
A laser is a very expensive apparatus. In the mutual connection of for instance stainless steel plates by laser welding the drawback is encountered that, even with automatic control, it is not possible to avoid the laser being cut of use for a time, for instance during transport for feed and outfeed of assemblies of objects to be joined together. In view of the relatively very high price of the laser, it is desirable to increase the time for which the laser is effectively in use.